2 * CDE - Common Desktop Environment
4 * Copyright (c) 1993-2012, The Open Group. All rights reserved.
6 * These libraries and programs are free software; you can
7 * redistribute them and/or modify them under the terms of the GNU
8 * Lesser General Public License as published by the Free Software
9 * Foundation; either version 2 of the License, or (at your option)
12 * These libraries and programs are distributed in the hope that
13 * they will be useful, but WITHOUT ANY WARRANTY; without even the
14 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
15 * PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with these libraries and programs; if not, write
20 * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
21 * Floor, Boston, MA 02110-1301 USA
23 /*%% (c) Copyright 1993, 1994 Hewlett-Packard Company */
24 /*%% (c) Copyright 1993, 1994 International Business Machines Corp. */
25 /*%% (c) Copyright 1993, 1994 Sun Microsystems, Inc. */
26 /*%% (c) Copyright 1993, 1994 Novell, Inc. */
27 /*%% $XConsortium: isindfreel.c /main/3 1995/10/23 11:41:03 rswiston $ */
30 * Copyright (c) 1988 by Sun Microsystems, Inc.
37 * Free list maintenance functions
40 #include "isam_impl.h"
42 extern Bufhdr *_isdisk_fix();
45 * blkno = _isfreel_alloc()
47 * Allocate a new index page.
51 _isindfreel_alloc(Fcb *fcb)
58 if (fcb->indfreelist == FREELIST_NOPAGE) {
61 * We must write something to the buffer, or we will get
62 * segmentation fault when using mapped I/O.
64 fcb->indsize = _extend_file(fcb, fcb->indfd, fcb->indsize);
66 return (fcb->indsize - 1);
69 pbhdr = _isdisk_fix(fcb, fcb->indfd, fcb->indfreelist, ISFIXWRITE);
70 p = pbhdr->isb_buffer;
72 npointers = ldshort(p + FL_NPOINTERS_OFF);
75 blkno = ldblkno(p + FL_POINTERS_OFF + npointers * BLKNOSIZE);
77 stshort((short)npointers, p + FL_NPOINTERS_OFF);
79 return (ldblkno(p + FL_POINTERS_OFF + npointers * BLKNOSIZE));
82 blkno = fcb->indfreelist;
83 fcb->indfreelist = ldblkno(p + FL_NEXT_OFF);
96 _isindfreel_free(Fcb *fcb, Blkno blkno)
102 if (fcb->indfreelist != FREELIST_NOPAGE) {
103 pbhdr = _isdisk_fix(fcb, fcb->indfd, fcb->indfreelist, ISFIXWRITE);
104 p = pbhdr->isb_buffer;
106 npointers = ldshort(p + FL_NPOINTERS_OFF);
108 if (npointers < FL_MAXNPOINTERS) {
109 stblkno(blkno, p + FL_POINTERS_OFF + npointers * BLKNOSIZE);
111 stshort((short)npointers, p + FL_NPOINTERS_OFF);
118 pbhdr = _isdisk_fix(fcb, fcb->indfd, blkno, ISFIXWRITE);
119 p = pbhdr->isb_buffer;
121 /* Mark page to indicate that it is in the free list. */
122 stshort((short)PT_FREELIST, p + FL_TYPE_OFF);
124 stshort((short)0, p + FL_NPOINTERS_OFF);
125 stblkno(fcb->indfreelist, p + FL_NEXT_OFF);
127 fcb->indfreelist = blkno;